A refrigerator is an electronic appliance that is used to store items (e.g. food and containers) at freezing or lower temperatures or at a temperature slightly above freezing.
Although there are various method of opening and closing a storage compartment (i.e. a freezing compartment or a refrigerating compartment) defined in the refrigerator, the opening and closing methods are generally classified into a method using a hinged door (e.g., a single door or double doors), provided at the front side of the storage compartment, and a method using a sliding door provided at the top side of a drawer type storage compartment, which is able to be wholly introduced into or discharged from the refrigerator.
Among these, a hinged door type refrigerator may include, for example, a home bar, an icemaker, a shelf, or a box mounted on the rear surface of the door. In the case of this type of refrigerator, when the door is closed, the front end of a item storage unit (e.g. a shelf, a drawer or a box) that is provided inside the storage compartment may interfere with the constituent elements mounted on the rear surface of the door (e.g. the home bar, icemaker, shelf or box).
In order to solve the interference described above, the front end of the item storage unit that is provided inside the storage compartment is located at a position spaced apart rearward from the front end of the storage compartment by a prescribed distance. However, in this case, the user needs to suffer the inconvenience of placing his/her hand deep inside the storage compartment in order to retrieve items placed in the item storage unit and has difficulty in visually identifying items stored in the rear region of the storage compartment. In particular, when the refrigerator is large, and thus has a long front-to-back length, the inconvenience of the user is worsened.
As efforts to remove the inconvenience of the user described above, a refrigerator has been developed, which includes a frame, which is movable in the front-to-back direction and supports item storage units arranged in multiple layers inside the storage compartment, and a link assembly, which connects the movable frame to a hinged door. In this case, when the door is opened, the movable frame is moved forward so as to move the item storage units forward.
The related art has a limitation as to the distance by which the movable frame is movable forward relative to the storage compartment. That is, even if the door is completely opened, the movable frame is adapted to stop when the front end of the item storage unit approaches the front end of the storage compartment. This is because the constituent elements on the rear surface of the door are mounted so as to protrude from the rear surface of the door by a prescribed distance, and therefore the protruding constituent elements may still be located in the forward movement path of the item storage unit and interfere with the item storage unit even after the door is opened. In addition, assuming that the movable frame protrudes beyond the front end of the storage compartment, the structure of a connecting portion between the movable frame and the item storage unit supported by the movable frame becomes unstable, which results in a requirement for excessively increased structural strength.
Frictional force, which prevents the movable frame from moving forward, is theoretically proportional to the sum of the weight of the movable frame and the load applied to the movable frame by the item storage unit and items stored therein.
In the case where the movable frame supports the item storage units that are arranged in multiple layers as in the related art, the weight of the movable frame is necessarily increased. This is because the number of members constituting the movable frame or the cross section of each member needs to be increased in order to ensure that the movable frame stably supports the loads of the item storage units arranged in multiple layers and the items stored therein. When the weight of the movable frame increases, consequently, the frictional force caused by the movement of the movable frame increases.
In the related art, the movable frame is supported by guide rails which are secured to the inner surface of the storage compartment. The guide rails guide the movement of the movable frame in the front-to-back direction.